In-situ measurement of the electron spin polarization by controlling its distribution in atomic ensembles.

The determination of electron spin polarization by controlling the atomic population distributions of ground states has been proposed. The polarization could be deduced by generating different population symmetries by polarized lights. The polarization of the atomic ensembles was decoded from optical depth in different transmissions of linearly and elliptic polarized lights. The feasibility of the method has been validated theoretically and experimentally. Moreover, the influences of relaxation and magnetic fields are analyzed. The transparency induced by high pump rates are investigated experimentally, and the influences of ellipticity of lights are also discussed. The in-situ polarization measurement was achieved without changing optical path of atomic magnetometer, which provides a new way to interrogate the performance of atomic magnetometer and in-situ monitoring the hyperpolarization of nuclear spins for atomic co-magnetometer.